Touch display device and method of manufacturing of the same

ABSTRACT

The present disclosure provides a touch display device including: a plurality of emitting elements; an adhesive layer over the emitting elements; a first touch electrode and a second touch electrode over the adhesive layer and in an active area; a pad electrode over the adhesive layer and in a touch pad region; and a protection layer over the first touch electrode, the second touch electrode and the pad electrode, wherein the first and second touch electrode are insulated by an insulating layer, and the protection layer includes at least one contact hole corresponding to the pad electrode, and wherein the pad electrode includes a plurality of electrode layers, and one of the plurality of electrode layers extends from the first touch electrode or the second touch electrode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of co-pending U.S. patent applicationSer. No. 17/082,605, filed on Oct. 28, 2020, which claims priority toand the benefit of Republic of Korea Patent Application No.10-2019-0146437 filed in the Republic of Korea on Nov. 15, 2019. Each ofthe above prior U.S. and Republic of Korea patent applications is herebyincorporated by reference.

BACKGROUND Technical Field

The present disclosure relates to a touch display device, and moreparticularly, to a touch display device being capable of minimizing adefect and a manufacturing method of the touch display device.

Description of the Related Art

A touch sensor is installed in a flat panel display device, e.g., aliquid crystal display (LCD) device, a field emission display (FED)device, a plasma display panel (PDP), an electroluminescent displaydevice or an electrophoretic display device, and is an input device toinput predetermined information by user's press or touch while viewingthe display device.

The touch senor for the display devices may be classified into an add-ontype touch screen panel (touch sensor), an on-cell type touch screenpanel and an integrated type (or an in-cell type) touch screen panel. Inthe add-on type touch screen panel, after a display panel and a touchscreen panel are independently manufactured, the touch screen panel isattached on an upper substrate of the display panel. In the on-cell typetouch screen panel, elements (or members) for the touch sensor areformed on a surface of an upper substrate of a display panel. In theintegrated type touch sensor, the touch sensor is included inside adisplay panel.

Recently, a flexible or foldable touch display device is developed.Particularly, the touch sensor or the touch screen panel is widelyapplied to an organic light emitting display (OLED) device as theflexible or foldable display device.

As a touch sensor used for a flexible, bendable, or foldable touchdisplay device, various types of touch sensors, i.e., the add-on type,the on-cell type or the integrated type, can be used. However, since theadd-on type touch display device, which is manufactured by attaching thetouch panel on the display panel, has relatively thick, it is difficultto realize a flexible or foldable display device.

On the other hand, the integrated type touch sensor is most frequentlyused to the flexible or foldable OLED device. However, since anencapsulation layer (or encapsulating film), which includes an organicmaterial and/or an inorganic material, is required in the OLED device tominimize moisture or oxygen penetration, a manufacturing method of theintegrated touch OLED device is complicated. In addition, the integratedtouch OLED device may be easily damaged by the bending stress which maybe occurred in a folding operation.

In the on-cell type touch OLED device, the touch sensor may be disposedor bonded on the encapsulation layer. In addition, the on-cell typetouch sensor can be applied to display devices other than the OLEDdevice.

In a bonding method of the on-cell type touch display device, the touchsensor is electrically connected to a pad region for transmitting andreceiving data. The pad region is disposed on the outside, not on theinside, where the touch sensor and the display substrate are bonded.However, defects may occur due to the above-mentioned structure.

Specifically, in order to manufacture a touch sensor by the bondingmethod, after the touch sensor is formed using a temporary manufacturingsubstrate, a step of bonding the touch sensor on the temporarymanufacturing substrate with the display panel is performed.

After the touch sensor disposed on the temporary manufacturing substrateis attached to the display panel, the temporary manufacturing substrateis removed (separated). However, in the manufacturing method of thetouch display device, the pad region for transmitting and receiving dataof the touch sensor may not be smoothly separated from the temporarymanufacturing substrate such that defects may be generated.

SUMMARY

Accordingly, embodiments of the present disclosure are directed to atouch display device and a manufacturing method of the same thatsubstantially obviate one or more of the problems due to limitations anddisadvantages of the related art, and have other advantages.

Additional features and advantages of the disclosure will be set forthin the description which follows, and in part will be apparent from thedescription, or may be learned by practice of the disclosure. Theobjectives and other advantages of the disclosure will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages in accordance with the purpose ofthe embodiments of the present disclosure, as described herein, anaspect of the present disclosure is a touch display device comprising: aplurality of emitting elements; an adhesive layer over the emittingelements; a first touch electrode and a second touch electrode over theadhesive layer and in an active area; a pad electrode over the adhesivelayer and in a touch pad region; and a protection layer over the firsttouch electrode, the second touch electrode and the pad electrode,wherein the first and second touch electrode are insulated by aninsulating layer, and the protection layer includes at least one contacthole corresponding to the pad electrode, and wherein the pad electrodeincludes a plurality of electrode layers, and one of the plurality ofelectrode layers extends from the first touch electrode or the secondtouch electrode.

Another aspect of the present disclosure is a method of manufacturing atouch display device comprising: forming a sacrificial layer on atemporary substrate; forming a protection layer including a contact holein a touch pad region on the sacrificial layer; forming a first padelectrode in the touch pad region; forming a first touch electrode onthe protection layer and a second pad electrode on the first padelectrode; attaching the temporary substrate and a display substrate;and removing the temporary substrate and the sacrificial layer.

It is to be understood that both the foregoing general description andthe following detailed description are examples and are explanatory andare intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this application, illustrate aspect of the disclosure andtogether with the description serve to explain principles of thedisclosure.

FIG. 1 is a schematic plane view of a touch display device according toan embodiment of the present disclosure.

FIGS. 2A and 2B are schematic cross-sectional views taken along thelines I-I′ and II-IF of FIG. 1 , respectively.

FIG. 3 is a schematic plane view illustrating a touch pad region of atouch display device according to an embodiment of the presentdisclosure.

FIGS. 4A and 4B are schematic cross-sectional views taken along thelines and IV-IV′ of FIG. 3 , respectively.

FIGS. 5A to 5E are schematic cross-sectional views illustrating amanufacturing method of a touch display device according to anembodiment of the present disclosure.

DETAILED DESCRIPTION

As mentioned above, the pad region may be damaged in the on-cell typetouch display device. The inventors of the present disclosure haveinvented a touch display device (or a touch display apparatus) and amanufacturing method of the same being capable of minimizing defectsthat may occur in the process of manufacturing the touch display deviceincluding an on-cell type touch sensor.

The present disclosure may provide a touch display device being capableof minimizing defects occurred in a manufacturing process for a padregion for transmitting and receiving touch-related data.

The present disclosure may provide a touch display device being capableof minimizing defect yield in a manufacturing process for a pad regionfor transmitting and receiving touch signal.

The present disclosure is not limited to the above-mentioned objects,and other objects will be clearly understood by those skilled in the artfrom the following description.

Advantages and technical features of the present disclosure, and methodsfor achieving the advantages and the technical features will beclarified with reference to embodiments described below in detailtogether with the accompanying drawings. However, the present disclosureis not limited to the embodiments disclosed below, but will beimplemented in various different forms. The embodiments allow thedisclosure of the present disclosure to be complete and the ordinaryskilled in the art to fully understand. The present disclosure is onlydefined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, etc., disclosed in thedrawings for describing the embodiments of the present invention areexemplary, and the present invention is not limited to the drawings. Thesame reference numerals refer to the same components throughout thespecification. In addition, in the description of the presentdisclosure, when it is determined that detailed descriptions of relatedknown technologies may unnecessarily obscure the subject matter of thepresent disclosure, detailed descriptions thereof will be omitted. When‘include’, ‘have’, ‘consist of’, etc., are used in this specification,other parts may be added unless ‘only’ is used. When a component isexpressed as a singular number, the plural number is included unlessotherwise specified.

In interpreting the components, it is interpreted as including the errorrange even if there is no explicit description.

In the case of the description of the positional relationship, forexample, when the positional relationship of two parts is described as‘on’, ‘over’, ‘under’, ‘at a side’, etc., one or more other parts may bepositioned between the two parts unless ‘right’ or ‘direct’ is used.

Terms ‘first’, ‘second’, etc., are used to describe various components,but these components are not limited by these terms. These terms areonly used to distinguish one component from another component.Accordingly, the first component mentioned below may be the secondcomponent within the technical spirit of the present disclosure.

Each of features of the various embodiments of the present disclosuremay be partially or wholly combined or mixed with each other, andtechnically various interlocking and driving is possible. Each of theembodiments may be independently implemented with respect to each otheror may be implemented together in an association relationship.

Reference will now be made in detail to aspect of the disclosure,examples of which are illustrated in the accompanying drawings.

FIG. 1 is a schematic cross-sectional view of a touch display deviceaccording to an embodiment of the present disclosure, and FIGS. 2A and2B are schematic cross-sectional views taken along the lines I-I′ andII-IF of FIG. 1 , respectively.

Referring to FIGS. 1, 2A and 2B, a touch display device 100 includes adisplay substrate DSP and a touch substrate TSP. The display substrateDSP may be an organic light emitting display substrate, but it is notlimited thereto.

The display substrate DSP may include a substrate PI, which includes anactive area AA and first and second bezel areas BA1 and BA2, a lightemitting element LS, which includes an anode, an organic emitting layerand a cathode, over the substrate PI and a thin film transistor (TFT) onthe substrate PI for controlling the light emitting element LS accordingto a driving signal.

The display substrate DSP and the touch substrate TSP may have astructure that is bonded by an adhesive layer AL, and the adhesive layerAL may be an epoxy-based adhesive layer. The adhesive layer AL may havea structure that is directly adjacent or directly contacts anencapsulation layer ENC of the display substrate DSP and a secondinsulating layer Passi of the touch substrate TSP.

The organic emitting layer in the light emitting element LS is liable tobe penetrated by oxygen and moisture. Accordingly, the organic emittinglayer may be covered by the encapsulation layer ENC to minimize thepenetration of oxygen and moisture into the light emitting element LS.

The encapsulation layer ENC may further include an absorbent or anano-material for improving the light efficiency of light emitted fromthe light emitting element LS. In addition, the encapsulation layer ENCmay include a plurality of layers, in which an organic material layerand an inorganic material layer are alternately stacked, and may furtherinclude various configurations for preventing cracks in order to providea flexible display device. The explanation to this configuration isomitted.

The light emitting element LS including the anode, the organic emittinglayer, and the cathode is controlled by a circuit unit including theTFT. Electrical signals and current for such control may be suppliedthrough a circuit board connected to a data pad DP.

The light emitting element LS controls the amount of light and variouswavelengths of light of the plurality of light emitting elements LS todisplay a desired image. The light emitting element LS may furtherinclude a color filter layer.

The substrate PI of the display substrate DSP may be a polyimidesubstrate to be used for a flexible display device or a foldable displaydevice and may have a multi-layered structure.

On the other hand, the display substrate DSP may further include aplanarization layer FL for the arrangement of the light emittingelements LS. The planarization layer FL may be made of a material suchas photo-acryl and may include a plurality of layers such that the lightemitting elements LS, the TFT and the signal lines, e.g., the datalines, which are connected to the TFT, may be disposed on or over theplanarization layer FL or between the plurality of layers.

The data lines may be electrically connected to a data pad DP in thesecond bezel area BA2. In this instance, the data pad DP may be notcovered by the touch substrate TSP for connection with the circuitboard.

On the other hand, the touch substrate TSP may include at least onetouch pad region, e.g. touch pad regions TP1 and TP2, to transmit theelectrical signal from the touch sensor to the circuit board. The touchpad regions TP1 and TP2 may be disposed in the first bezel area BA1 ofthe touch substrate TSP.

The touch substrate TSP has the active area AA and the first bezel areaBA1. The touch substrate TSP includes a protection layer PAC, a firstinsulating layer ILD, the second insulating layer Passi, a first touchelectrode TX and a second touch electrode RX.

Although not shown, each of the first touch electrode TX and the secondtouch electrode RX constituting the touch sensor may be touch electrodeshaving a metal mesh shape. The first touch electrode TX and the secondtouch electrode RX are insulated by the first insulating layer ILD.

Each of the first touch electrode TX and the second touch electrode RXmay be made of a transparent conductive material, e.g., indium-tin-oxide(ITO), indium-zinc-oxide (IZO), or gallium-doped zinc oxide (GZO), or ametallic material, e.g., titanium (Ti), aluminum (Al), copper (Cu), ormolybdenum (Mo). Each of the first touch electrode TX and the secondtouch electrode RX may have a single-layered structure or amulti-layered structure.

The touch pad regions TP1 and TP2 include at least one pad electrode PE.The pad electrode PE may have a multi-layered structure including atleast one metal or conductive material. The protection layer PAC mayhave an open section for electrical connection with a circuit board.

The protection layer PAC may have functions of photo-resist (PR) and apassivation layer. For example, the protection layer PAC may be formedof an organic material having low dielectric constant.

Referring to FIGS. 2A and 2B, at least one electrode layer of the padelectrode PE may be an electrode formed by extension of the first touchelectrode TX or the second touch electrode RX. Namely, one of the firstand second touch electrodes TX and RX may extend into one of the touchpad regions TP1 and TP2 and the other one of the first and second touchelectrodes TX and RX may extend into the other one of the touch padregions TP1 and TP2 to form the at least one electrode of the padelectrode PE. As a result, as shown in FIG. 2A, the pad electrode PE inthe first touch pad region TP1 is electrically connected to the firsttouch electrode TX, while the pad electrode PE in the second touch padregion TP2 is electrically connected to the second touch electrode RX.Alternatively, as shown in FIG. 2B, the pad electrode PE in the firsttouch pad region TP1 is electrically connected to the second touchelectrode RX, while the pad electrode PE in the second touch pad regionTP2 is electrically connected to the first touch electrode TX.

In FIGS. 2A and 2B, the pad electrode PE in the first touch pad regionTP1 extends from one of the first and second touch electrodes TX and RX,and the pad electrode PE in the second touch pad region TP2 extends fromthe other one of the first and second touch electrodes TX and RX.Alternatively, the pad electrode PE may be connected to one of the firstand second touch electrodes TX and RX by a routing line.

A plurality of first touch electrodes TX and a plurality of second touchelectrodes RX are disposed on the touch substrate TSP. Since the firsttouch electrode TX and the second touch electrode RX cross each otherwith the first insulating layer ILD interposed therebetween, a mutualcapacitance is formed therebetween. Accordingly, when the touchsubstrate TSP is touched, the mutual capacitance between the first touchelectrode TX and the second touch electrode RX is changed. Thecoordinates of the touch position can be detected by measuring thechange of the mutual capacitance.

FIG. 3 is a schematic plane view illustrating a touch pad region of atouch display device according to an embodiment of the presentdisclosure, and FIGS. 4A and 4B are schematic cross-sectional viewstaken along the lines and IV-IV′ of FIG. 3 , respectively.

Referring to FIGS. 3 and 4A to 4B, the touch pad region has a pluralityof open sections (or openings) OP. The open section OP is a contact holethat exposes a portion of the pad electrode PE, and the exposed padelectrode PE is electrically connected to a flexible substrate or acircuit board by using a connection element such as a conductive ball.

The single pad electrode PE may correspond to the plurality of opensections OP. Namely, the pad electrode PE may correspond to two or morecontact holes. The open section (OP) may have a polygonal shape such asa rectangular shape, pentagonal shape or hexagonal shape. As describedbelow, the step of removing the temporary substrate in the manufacturingprocess of the touch substrate TSP using the temporary substrate isessential. A laser lift-off (LLO) process is performed in the step ofremoving the temporary substrate.

In the process of removing the temporary substrate with the LLO process,the heat by the laser, which is applied to the pad electrode PE, is moreuniformly dissipated in the open section OP of the hexagonal shape thanin the open section OP of the rectangular shape. In addition, a thermalstress to an adjacent element by the open section OP of the hexagonalshape is decreased in comparison to the open section OP of therectangular shape. Accordingly, the open section OP of the hexagonalshape is preferred.

The uniformity of heat transfer and heat dissipation can minimizeanomalies in the adhesive strength between the pad electrode PE and thetemporary substrate during the LLO process such that defects such astearing of the pad electrode PE can be minimized or prevented.

Referring to FIGS. 4A and 4B, the pad electrode PE may have amulti-layered structure including at least one electrode layer.

As mentioned above, the pad electrode PE includes an electrode layerextending from the first touch electrode TX or the second touchelectrode RX. The pad electrode PE may be electrically connected to thefirst touch electrode TX or the second touch electrode RX.Alternatively, the pad electrode PE may be electrically connected to thefirst touch electrode TX or the second touch electrode RX by a separatewiring electrode, i.e., the routing line.

The pad electrode PE includes a first pad electrode BE as a top layer.The first pad electrode BE may be disposed to correspond to the opensection OP of the protection layer PAC. The first pad electrode BE maybe disposed to fill the inner side surface of the open section OP in theprotection layer PAC according to the arrangement order of the first padelectrode BE and the protection layer PAC. Namely, as shown in FIG. 4A,a center of the first pad electrode BE may correspond to the opensection OP in the protection layer PAC to be exposed through the opensection OP, and edges of the first pad electrode BE may contact the sidesurface of the protection layer PAC in the open section OP.Alternatively, as shown in FIG. 4B, a center of the first pad electrodeBE may correspond to the open section OP in the protection layer PAC tobe exposed through the open section OP, and edges of the first padelectrode BE may be covered by the protection layer PAC. The protectionlayer PAC may be disposed between the first pad electrode BE and asecond pad electrode TE.

The pad electrode PE may be an electrode layer including a plurality ofelectrode layers (sub-layers) as described above. For example, the padelectrode PE may include the first pad electrode BE, the second padelectrode TE, which is formed of the same material and disposed on thesame layer as the first touch electrode TX, and a third pad electrodeRE, which is formed of the same material and disposed on the same layeras the second touch electrode RX. Namely, the pad electrode PE may havea triple-layered structure. Alternatively, the pad electrode PE may havea double-layered structure including the first pad electrode BE and thesecond pad electrode TE without the third pad electrode RE or the firstpad electrode BE and the third pad electrode RE without the second padelectrode TE. Since the pad electrode PE needs to maintain a certainthickness in the electrical connection using the circuit board and theconductive ball, the required thickness of the pad electrode PE may beprovided by forming the pad electrode PE of the same metallic materialas the first and second touch electrodes TX and RX in the step offorming the first and second touch electrodes TX and RX. In addition, awiring electrode for electrical connection between the pad electrode PEand the touch sensor can be formed at the same time.

A barrier layer BR is disposed on the protection layer PAC to improvethe uniformity of the touch signal. When the barrier layer BR isdisposed, the film releasing (or separating) problem may occur in aperipheral region of the substrate. A plasma treatment may be performedon the barrier layer BR to prevent the above problem.

The open section OP in the protection layer PAC may be a reverse-taperedshape with respect to a surface of the adhesive layer AL or thesubstrate PI of the display substrate DSP.

The first pad electrode BE is plasma-treated together in the process ofplasma treatment to increase the adhesion strength of the protectionlayer PAC. Namely, any one layer of the first pad electrode BE may be aplasma-treated electrode layer.

FIGS. 5A to 5E are schematic cross-sectional views illustrating amanufacturing method of a touch display device according to anembodiment of the present disclosure.

The explanation of the manufacturing method of the touch display deviceis focused on a step of forming the pad electrode.

The touch substrate TSP including the touch sensor is formed using atemporary substrate SUB. Since a glass substrate has an advantage in alaser lift-off (LLO) process using a laser, the temporary substrate SUBmay be a glass substrate.

In a method of manufacturing a touch display device using the glasssubstrate as the temporary substrate SUB, a sacrificial layer SL isdisposed (formed) on the glass substrate, and then a protection layerPAC is disposed on the sacrificial layer SL, as shown in FIG. 5A.

The sacrificial layer SL may be hydrogenated amorphous silicon (a-Si:H)or hydrogenated and doped amorphous silicon (a-Si:Hn+ or a-Si:H;p+).

The hydrogen of the sacrificial layer SL is combined (connected orbonded) with the silicon of the temporary substrate SUB. When the laseris irradiated, the combination (connection or the bond) between thehydrogen of the sacrificial layer SL and the silicon of the temporarysubstrate SUB are cut off such that the separation of the temporarysubstrate SUB becomes easier.

The protection layer PAC is disposed on the sacrificial layer SL. Forexample, the protection layer PAC may be an organic insulating layer ofphoto-acryl. A plurality of open sections OP are formed in theprotection layer PAC. A portion of the sacrificial layer SL is exposedthrough the open section OP in the protection layer PAC. The opensection OP is formed by removing a portion of the protection layer PAC.For example, the portion of the protection layer PAC may be removed by adry-etching process or a wet-etching process. The protection layer PAChas a tapered shape with respect to the temporary substrate SUB. Namely,with respect to the temporary substrate SUB, an upper portion of theopen section OP has a width (area) greater than a lower portion of theopening section OP.

As shown in FIG. 5B, the first pad electrode BE is disposed on theprotection layer PAC. For example, the first pad electrode BE mayinclude a single metal layer, such as a molybdenum (Mo) layer or anindium-tin-oxide (ITO) layer, or a multiple metal layers, such as Mo/A1or Mo/Al/Mo. The first pad electrode BE may be disposed to cover theopen section OP in the protection layer PAC. As will be described later,the single pad electrode may include a plurality of first pad electrodesBE respectively covering the plurality of open sections OP. The firstpad electrodes BE in adjacent open sections OP are spaced apart fromeach other. The first pad electrode BE in the open section OP contactsthe portion of the sacrificial layer SL exposed through the open sectionOP. In addition, the first pad electrode BE may cover a side surface ofthe protection layer PAC in the open section OP. Adjacent two first padelectrodes BE are spaced apart from each other in a top surface of theprotection layer PAC between adjacent two open sections OP.

Thereafter, a plasma treatment process is performed on the protectionlayer PAC to improve an adhesion strength at the interface. In thisinstance, the first pad electrode BE arranged in the open section OP isalso plasma-treated. The plasma treatment process is performed using anionized gas such as argon (Ar), oxygen (O₂), hydrogen (H₂) and nitrogen(N₂). The adhesion strength between the barrier layer BR and each of theprotection layer PAC and the first pad electrode BE and/or between thesecond pad electrode TE and the first pad electrode BE are improved bythe plasma treatment to the protection layer PAC and/or the first padelectrode BE such that the problem of defects in a flexible environmentis minimized or prevented. Namely, since a surface of the protectionlayer PAC and a surface of the first pad electrode BE areplasma-treated, an adhesion strength between the protection layer PACand the barrier layer BR and an adhesion strength between the first padelectrode BE and the second pad electrode TE are improved. In otherwords, in a case that the touch substrate TSP and the display substrateDSP are attached, an interface between a lower surface of the first padelectrode BE, which is disposed at an uppermost position, an uppersurface of the second pad electrode TE, which is adjacent to the firstpad electrode BE, is plasma-treated.

When the sacrificial layer SL on the temporary substrate SUB is exposedto the plasma treatment process, there may be a problem in the laserlift-off process of the sacrificial layer SL. However, in the presentdisclosure, since the plasma treatment is performed after the first padelectrode BE, which covers the open section OP, the sacrificial layer SLon the temporary substrate SUB is not exposed to the plasma treatmentprocess such that the problem in the laser lift-off process isprevented.

In the above-described configuration, the arrangement order of the firstpad electrode BE and the protection layer PAC may be changed. In thiscase, after the first pad electrode BE is disposed on the sacrificiallayer SL, the protection layer PAC is disposed. The open section OP maybe formed in the protection layer PAC by forming a contact holecorresponding to the first pad electrode BE. By performing the plasmatreatment process onto the protection layer PAC and the first padelectrode BE after the protection layer PAC is formed, the same effectcan be obtained.

The arrangement order between the first pad electrode BE and theprotection layer PAC may be selectively changed. The first pad electrodeBE may be disposed on the inner surface of the open section OP accordingto the arrangement order. When the first pad electrode BE is disposedbefore the protection layer PAC is disposed, there is an advantage ofobtaining a more stable electrical connection characteristic inconnection with a circuit board using a conductive ball. On the otherhand, when the protection layer PAC is disposed before the first padelectrode BE is disposed, the electrical connection of the first padelectrode with another electrode, which is disposed by extending fromthe touch sensor over the first pad electrode BE, can be furtherimproved.

As shown in FIG. 5C, the barrier layer BR is disposed on the protectionlayer PAC to improve the uniformity of the touch signal. In the outerportion (peripheral portion) of the touch substrate TSP, where thebarrier layer BR and the sacrificial layer SL directly contact, thereleasing (separation) problem of the barrier layer BR from thesacrificial layer SL may occur. In the present disclosure, the plasmatreatment process is performed onto the protection layer PAC.

For example, the barrier layer BR may be formed to correspond to anupper surface and a side surface of the protection layer PAC. As aresult, in the open section OP, both ends of the first pad electrode BEare covered with the barrier layer BR, and a center of the first padelectrode BE is exposed. The barrier layer BR may be omitted.

Next, the first touch electrode TX, the second pad electrode TE, thefirst insulating layer ILD, the second touch electrode RX and the thirdpad electrode RE are sequentially formed. The first touch electrode TXand the second touch electrode RX are insulated by the first insulatinglayer ILD in the active area AA, while the second pad electrode TE andthe third pad electrode RE contact each other in the touch pad region toform the pad electrode PE.

In more detail, after the barrier layer BR is formed, the first touchelectrode TX and the second pad electrode TE are formed. The first touchelectrode TX and the second pad electrode TE are formed of the samematerial and spaced apart from each other. The second pad electrode TEin the open section OP contacts the first pad electrode BE.

Next, the first insulating layer ILD covering the first touch electrodeTX and exposing the second pad electrode TE is formed. Edges of thesecond pad electrode TE may be covered with the first insulating layerILD.

Next, the second touch electrode RX, which corresponding to the firsttouch electrode TX, is formed on the first insulating layer ILD, and thethird pad electrode RE extending from the second touch electrode RX isformed on the second pad electrode TE. The pad electrode PE in theopening section OP may have a triple-layered structure including thefirst to third pad electrodes BE, TE and RE, and the pad electrode PE onthe protection layer PAC between adjacent open sections OP may have adouble-layered structure including the second and third pad electrodesTE and RE.

Each of the first touch electrode TX, the second pad electrode TE, thesecond touch electrode RX and the third pad electrode RE may include asingle-layered structure of a metallic material, e.g., Al, AlNd, Mo,MoTi, Cu, or Cr, or a transparent conductive material, e.g.,indium-tin-oxide (ITO), indium-zinc-oxide (IZO) or gallium-doped zincoxide (GZO). Alternatively, each of the first touch electrode TX and thesecond touch electrode RX may include a double-layered structure of ametal layer and a transparent conductive material layer. When the firstand second touch electrodes TX and RX have the single-layered structure,the first and second touch electrodes TX and Rx may be arranged to forma mesh shape.

Next, the second insulating layer Passi is disposed on the pad electrodePE to protect the pad electrode PE and to provide a planar (or flat) topsurface.

As shown in FIGS. 5D and 5E, the temporary substrate SUB is removed(separated).

Particularly, as shown in FIG. 5D, the touch substrate TSP and thedisplay substrate DSP are attached by an adhesive layer AL. The adhesivelayer AL may be an epoxy adhesive. Namely, the touch substrate TSP andthe display substrate DSP are attached such that the second insulatinglayer Passi of the touch substrate TSP faces the display substrate DSP.

After the touch substrate TSP and the display substrate DSP areattached, a laser is irradiated onto a rear surface of the temporarysubstrate SUB. The hydrogen in amorphous silicon of the sacrificiallayer SL is dehydrogenated by the laser such that a surface of thesacrificial layer SL bursts. As a result, the sacrificial layer SL withthe temporary substrate SUB are separated from the protection layer PAC.

Next, a wet-etching process using an acid solution or the like may beoptionally performed to remove a residue of the sacrificial layer SL onthe protection layer PAC and the first pad electrode BE.

The laser in the process of separating the temporary substrate SUB maybe a diode pumped solid state (DPSS) laser or an excimer laser.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the aspects of thedisclosure without departing from the spirit or scope of the disclosure.Thus, it is intended that the present disclosure covers themodifications and variations of this disclosure provided they comewithin the scope of the appended claims and their equivalents.

What is claimed is:
 1. A display device, comprising: a light emittinglayer over a substrate; an adhesive layer over the light emitting layer;a first touch electrode over the adhesive layer and in an active area ofthe display device; a first pad electrode over the adhesive layer and ina touch pad region of the display device; and a protection layer overthe first touch electrode and the first pad electrode, the first padelectrode being exposed through an opening in the protection layer,wherein the first pad electrode has a greater width than the opening inthe protection layer.
 2. The display device of claim 1, and a portionthe first pad electrode contacts a side surface of the protection layerat the opening in the protection layer.
 3. The display device of claim1, further comprising: a second pad electrode under the protection layerand connected to the first pad electrode.
 4. The display device of claim3, further comprising: a barrier layer interposed between the first padelectrode and the second pad electrode.
 5. The display device of claim3, wherein the second pad electrode extends from the first touchelectrode.
 6. The display device of claim 3, further comprising: a thirdpad electrode under the protection layer and connected to the second padelectrode.
 7. The display device of claim 6, further comprising: asecond touch electrode between the adhesive layer and the protectionlayer in the active area of the display device, wherein the second padelectrode extends from one of the first touch electrode and the secondtouch electrode, and the third pad electrode extends from the other oneof the first touch electrode and the second touch electrode.
 8. Thedisplay device of claim 6, wherein the second pad electrode contacts thefirst pad electrode, and the third pad electrode contacts the second padelectrode.
 9. The display device of claim 6, wherein the first padelectrode, the second pad electrode, and the third pad electrode overlapwith one another in a plan view.
 10. The display device of claim 6,wherein the second pad electrode is disposed on a same layer as one ofthe first touch electrode and the second touch electrode, and the thirdpad electrode is disposed on a same layer as the other of the firsttouch electrode and the second touch electrode.
 11. The display deviceof claim 6, wherein each of the second pad electrode and the third padelectrode includes at least one of aluminum (Al), aluminum-neodymium(AlNd), molybdenum (Mo), titanium (Ti), molybdenum-titanium (MoTi),copper (Cu), chromium (Cr), indium-tin-oxide (ITO), indium-zinc-oxide(IZO), and gallium-doped zinc oxide (GZO).
 12. The display device ofclaim 11, wherein one or both of the second pad electrode and the thirdpad electrode have a multi-layered structure including an aluminum (Al)layer between two titanium (Ti) layers.
 13. The display device of claim1, further comprising: a second touch electrode between the adhesivelayer and the protection layer in the active area of the display device;and an insulating layer interposed between the first touch electrode andthe second touch electrode in the active area.
 14. The display device ofclaim 13, wherein the insulating layer is disposed under the protectionlayer in the touch pad region.
 15. The display device of claim 1,further comprising: an encapsulation layer between the light emittinglayer and the adhesion layer; and an organic light emitting diodeincluding the light emitting layer, wherein the encapsulation layercovers the organic light emitting diode.
 16. The display device of claim1, wherein the protection layer includes photo-acryl.
 17. The displaydevice of claim 1, wherein the opening in the protection layer has atapered shape.
 18. The display device of claim 1, further comprising acolor filter layer in the active area.
 19. The display device of claim18, further comprising a light emitting element including the colorfilter layer.
 20. The display device of claim 1, wherein the substrateincludes polyimide.
 21. The display device of claim 20, wherein thedisplay device is flexible or foldable.
 22. The display device of claim1, wherein the substrate has a multi-layered structure.
 23. The displaydevice of claim 1, further comprising a planarization layer on thesubstrate.
 24. The display device of claim 23, wherein the planarizationlayer includes a plurality of layers, and wherein the light emittinglayer is disposed over or between the plurality of layers of theplanarization layer.
 25. The display device of claim 1, furthercomprising: a thin film transistor interposed between the substrate andthe adhesive layer in the active area; and a data pad in a data padregion of the display device and electrically connected to the thin filmtransistor, wherein the data pad is not covered by the adhesive layer.26. The display device of claim 25, wherein the touch pad region isdisposed between the active area and the data pad region.
 27. Thedisplay device of claim 1, wherein the first touch electrode has a meshshape.
 28. The display device of claim 1, further comprising a routingline connected between the first pad electrode and the first touchelectrode.
 29. The display device of claim 1, further comprising apassivation layer interposed between the first pad electrode and theadhesive layer.